Better protecting standard airbox from heat? Removing flap.

[Anees]

Hi guys,

The airbox flap in my B7 RS4 has not been working; which he been why it seems my car has felt pretty flat at higher RPMS. After some diagnostics, I have for the moment cable tied the flap permanently open. The car runs much better top end because of this and feels a little more pokey lower down the rev range too.

The airbox flap isn't working because the sensor under the airbox that opens and closes it isn't working - common fault. Now I am considering my options.

1. Get the sensor replaced (£58 from TPS for part) and keep it as standard.
2. Remove flap all all together. (should I still replace the solonoid/sensor if I remove the flap- does it perform any other function?)

My concern with option 2 is heat soak. What I was thinking is maybe fit in an additional cold air feed if possible, and wrap the airbox with heat protective wrap. Should this be enough to prevent heat soak with the flap permanently removed?

I wouldn't mind a nice intake kit, but since they offer no performance increase (but do look awesome!) I would rather put the money towards an exhaust.

Advice appreciated.

Thanks
Anees

[Anees]

Was thinking of using this stuff:

http://www.ebay.co.uk/itm/Design-Engine ... 20d562503f

Expensive but hopefully worth it.

[Rick_RS4]

covered loads, try a search

CAI feed airbox

they should bring answers

[MikeFish]

Anees, the look of the intake kit is just a nice bonus, it is the sound of it that makes it worthwhile. And you have to do it before you get an exhaust otherwise the exhaust will probably drown out the lovely roar that it produces. I'd go with the intake kit if I was you. I wish I'd got mine a lot sooner.

[adsgreen]

A secondary bonus is that with a caf you only have one aux rad to fail

[Anees]

You've got me reading reviews of intakes now! lol

A few owners have said they notice sharper throttle response with the Revolution and similar intakes then the standard airbox. Why would this be?

[sonny]

What you have to realise is that by tying open the airbox flap, warm is being drawn in from the aux rad all the time now, it has nothing what so ever to with heat soak (heat soak would assume the airbox was getting hot by the exhaust manifold, which it does to the point where is hinders performance).

The airboix flaps sits behind the aux rad, air flows thought it, when driving at lower speeds/rev it remains closed for obvious reasons, at higher speeds it opens as there is a higher airflow. Remember the front snorkel lets a lot of air in too. If you are not getting the "kick" then you may have a vacuum related problem.

My advise would be to either, repair it and leave as it is or you could also remove aux rad, or remove the flap totally and invest in a CAF.

p.s even if you remove flap, you still need the sensor iirc

[MikeFish]

More noise = faster. Simples.

[Anees]

I've been doing more reading and as Sonny said the reason all the after market intakes do not really increase performance is because they suck in hot air from the aux radiator hence why Audi have the flap.

It seems that if the aux radiator is removed, which is a common mod, then coupled with a cold air feed, they really come into there own!! I've heard a few clips on you tube -anything that makes the sound more like a C63 the better!! I've contacted Revolution and they do have the intakes on offer so I think I am going to go with one!

Since my airbox flap sensor isn't working anyway and won't be needed with the intake, can the pipework to it just be plugged or do I still need to buy a new sensor?

I did say I wasn't going to do many mods to my RS4.........

[scaghead]

You won't be disappointed fella..I have the revolution intake ,and as mike says more noise equals faster in my book

[Anees]

Yes - I have an intake on my S2000 and that sounds glorious once VTEC kicks in (yo!) but on a v8 the noise should be something else!!

Only question I have about this now is since my airbox flap sensor isn't working anyway and won't be needed with the intake, can the pipework to it just be plugged or do I still need to buy a new sensor i.e does it do anything else since it is linked to the vacuum system?

Thanks

[Yanos]

I would ditch the air box and go for intake mate. Sounds better and you get the kick too. Just remember and seal off the vacuum line to the flap like I forgot do at first because I rushed it to hear the noise! I'm rather impatient.

[sonny]

Iirc you still need the sensor attached even if you de-flap /remove airbox. So it can send the relevant signals to the IM runner flaps or something like that ( cant remember now).

[MikeFish]

I don't remember plugging anything up. Everything you need comes with the revolution intake. Theres a little filter to plug the pipe for the secondairy air injection thingy, but I didn't secure mine properly and by the time I got to MRC it had disappeared, but it didn't matter as they removed the Secondary Air Injection as part of the CAI and other mods.

[adsgreen]

Iirc the unit is purely an actuator with no code signals to the ecu - after all when they fail (often) there very rarely any symptoms logged